Panplex question, Sperry SP-33

Jonathan Peakall

unread,

Oct 18, 2017, 3:03:10 PM10/18/17

to neoni...@googlegroups.com

Hi All,

Someone on another forums is having trouble with some panplex displays. He says that some digits light and others don't on all of them. They appear to be NOS. How likely is it that some segments are toast and others not? Sounds like cathode poisoning to me. If so, cooking them at a higher current might bring them back to life?

Thanks!

Jonathan

gregebert

unread,

Oct 18, 2017, 4:10:07 PM10/18/17

to neonixie-l

Used displays will get a faint tint on the glass; unused ones are crystal-clear.

Is it a multiplexed display ? Most likely it is, and I wonder if there is any confusion about the pinout.

Does it also include the driver, or is it strictly a bare display ?

Pictures would be helpful.

Ookpik

unread,

Oct 20, 2017, 3:21:03 PM10/20/17

to neonixie-l

Hi,

I’m the fellow who is trying to test the Panaplex displays. I have several SP-336 and SP-337 displays that after testing were found to either not work at all or only partially work.

The thread mentioned by Jonathan can be found here:

http://antiqueradios.com/forums/viewtopic.php?f=6&t=329168&sid=43ef8db9fe2b71654a90cc5d5745ff2d

Unfortunately, I do not have a DC power supply that goes above 160V.

If anyone has any additional suggestions or tips regarding the testing of these display it would be greatly appreciated!

gregebert

unread,

Oct 20, 2017, 4:01:27 PM10/20/17

to neonixie-l

If you have another power supply that's around 20V, such as a laptop power supply, you can put it in-series with your 160V supply. If you get 140V instead of 180V, just switch the polarity. Of course, you can only do this with a supply this is ungrounded. Other option is to put a few 9V batteries in series with the 160V supply.

You are right on the edge at 160V; the display may or may not ionize consistently.

It's very important to have a series resistor to limit the current, or use a power-supply that has a built-in current-limit. I believe those displays run around 300uA per segment for non-multiplexed operation. As long as the current is kept to a safe value (from datasheet), you wont harm a nixie/panaplex running at a higher voltage.

For basic testing, a single resistor is OK, but be careful because current is proportional to surface area; a decimal-point or colon will use much less current than a segment for a number, so it needs a higher resistance.

When you have figured-out the pinout, and want to make it display something, you will need a resistor (or current-limiter) for each segment. DONT use a single anode resistor to limit the current for multiple segments. If you do, the more segments you turn on , the dimmer they will be.

I highly recommend that you get another power supply with a higher output voltage. A few years ago I designed my own nixie/dekatron power supply with current-limiting, and posted about it on this group. There's also a good HV supply mentioned in this group within the past 1-2 weeks.

Robert L

unread,

Oct 20, 2017, 11:33:52 PM10/20/17

to neonixie-l

Cross posting with another Panaplex thread...

Search for: "Sperry Panaplex 1973 catalog". You will find the following with a wealth of data on many of the relatively common Sperry displays out there... including pin-outs, drive currents, circuits, etc.

information displays:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&cad=rja&uact=8&ved=0ahUKEwj1pMG_44DXAhWohVQKHbPWCNUQFghAMAY&url=http%3A%2F%2Fwww.waynekirkwood.com%2Fimages%2Fpdf%2FSperry_Information_Displays_Catalog_1973.pdf&usg=AOvVaw1W-p-iUcgp-fofU-o4Vd-b

clock displays:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&cad=rja&uact=8&ved=0ahUKEwj1pMG_44DXAhWohVQKHbPWCNUQFghGMAc&url=http%3A%2F%2Fwww.waynekirkwood.com%2Fimages%2Fpdf%2FSperry_Gas_Discharge_Clock_Display_Catalog_1973.pdf&usg=AOvVaw3udU-p-JwF8WvpsXZDH3Ga

Regards,

Bob

Manuel Azevedo

unread,

Oct 21, 2017, 3:53:23 AM10/21/17

to neonixie-l

I got 3 SP-352 yesterday, only one works 100%.

The other has all segments good, except one, that only shows half segment. I wonder why?

The last one is completely empty - doesn't glow when using a plasma globe next to it.

I've seen somewhere that new displays should have a shinny look - most of the listings I found, the displays have that "old look", like burnt - this also happens with my working display, so I wonder.

Still, they look awesome when lit.

Nick

unread,

Oct 21, 2017, 8:50:18 AM10/21/17

to neonixie-l

You need more than 160V to be sure the display starts ionising - it may sustain at 160V, but you need more volts - note that the segments on these displays use very little current and you will need s large (say 470K) cathode resistor.

I have several 100 Panaplex displays, including over 100 SP-336s in stock. The 336s were bought NOS in original packing from a reputable source (Jan W.) some years ago - about 10% were completely dead (Jan dealt with that - he's excellent - he also has the original testing machine for ZM-1350s! It's a beast - https://www.die-wuestens.de/dindex.htm?/ZM1350.htm

So, it's possible that some have simply died of old age/leakage. But if they've been unused/in storage for a long time they can be "sticky" when being lit again, so don't give up - if you've got a neon tester or a Tesla coil etc. that you can stick them near, they should light up - if they do that, they haven't out-gassed, so you have a chance.

Using a high cathode resistor, I'd crank them up past 200V or until they light, then drop back to 180V or so and let them settle down again.